In vitro gene expression changes of androgen receptor coactivators after hormone deprivation in an androgen-dependent prostate cancer cell line.

BACKGROUND AND PURPOSE: Androgen receptor (AR) coactivators modulate the transcriptional activity of AR and may activate AR-associated genes upon androgen deprivation. Changes of expression patterns may help reveal the role of AR cofactors in androgen-independent prostate cancer. This study investigated changes of expression patterns of several AR coactivators after androgen deprivation in an androgen-dependent prostate cancer cell line (LNCaP). METHODS: LNCaP cells were cultured in RPMI medium with charcoal/dextran-treated fetal bovine serum for 28 days. Samples of total RNA collected at 1-week intervals were analyzed using a non-isotopic multi-probe ribonuclease protection assay system with a human AR multi-probe template set. Expression changes of 10 mRNAs of interest (AR, Rb, ARA160, ARA24, ARA54, ARA55, ARA70, BRCA1, F-SRC-1, and RAC3) were analyzed simultaneously as AR and AR-associated cofactors in 1 hybridization reaction. RESULTS: Seven of 10 cofactors tested were expressed in LNCaP cells. Only Rb, ARA55 and BRCA1 were not detected. LNCaP cells cultured in charcoal-treated serum for 28 days clearly showed more than 1.5-fold increases in AR, ARA160, and ARA70 expression, while expression of ARA24 and ARA54 increased less than 1.5-fold. Only RAC3 and F-SRC-1 decreased in RNA expression. Cell morphology features changed gradually into neuron-like shapes with elongated cytoplasm during the culture period. Cell growth almost ceased 28 days after the start of culture. CONCLUSION: The changes in expression pattern of AR and AR cofactors and in particular the remarkable increase in AR, ARA160 and ARA70 support the role of AR cofactors in modulating prostate cancer cell growth from androgen dependence to androgen independence.